Search Results (45)

Background: Hospitalized COVID-19 patients are particularly vulnerable to secondary bacterial infections, which can significantly worsen clinical outcomes. The aim of the study was to identify the cause of bacteremia in a group of hospitalized COVID-19 patients and find out the source of the outbreak to prevent further spread. Methods: Pathogen identification in blood cultures and sensitivity testing were carried out using the automated VITEK2 system. A total of 110 samples were tested; these were collected from patients’ colonization sites and from surfaces, materials and fluids used in the setting. Furthermore, multilocus sequence typing (MLST) and next-generation sequencing (NGS) were employed to characterize the isolates. Results: Achromobacter xylosoxidans was detected in the blood of nine hospitalized patients and in cotton used for disinfection; all isolates presented an identical antibiotic resistance pattern, and all carried the bla_OXA-114 gene which is intrinsic to this species. Infection control measures were implemented promptly. With one exception, all patients recovered and were discharged in good health. Conclusions: This outbreak underscores the urgent need for investigation and control of hospital infections, as bacteremia is associated with increased morbidity, mortality, hospitalization time, and cost. It also highlights the importance of close collaboration among healthcare professionals. Full article

Background/Objectives: Achromobacter xylosoxidans and Achromobacter insuavis are emerging opportunistic pathogens. Several Resistance-Nodulation-cell Division (RND) efflux systems are involved in intrinsic or acquired antibiotic resistance (AxyABM, AxyXY-OprZ, and AxyEF-OprN). The aim of this study was to explore the resistance mechanisms in one-step mutants in which the efflux systems described to date are not involved: one mutant of A. insuavis AXX-A (AXX-A-Do1) and two mutants of A. xylosoxidans CIP102236 (CIP102236-El9 and CIP102236-Eo4) selected on fluoroquinolones. Methods: In vitro mutants were compared to parental isolates by WGS. RT–qPCR and gene inactivation were used to explore the role of the new efflux systems detected. Results: In the A. insuavis AXX-A mutant (AXX-A-Do1), WGS showed a substitution in the putative regulator of the new RND efflux system AinCDJ. The transporter gene ainD was 79-fold overexpressed in AXX-A-Do1, compared to its parental strain. The inactivation of ainD in AXX-A-Do1 led to a decrease in MICs of ciprofloxacin (8-fold), levofloxacin (8-fold), cefepime (≥8-fold), meropenem (4-fold), doripenem (4-fold), doxycycline (4-fold), minocycline (4-fold), tigecycline (4-fold) and chloramphenicol (≥8-fold). The MICs values obtained were similar to those of the parental strain AXX-A. The same approach allowed the detection of the new efflux system AxySUV in A. xylosoxidans CIP102236 mutants, in which substitutions in the putative AxySUV regulator were associated with the overexpression of the transporter gene axyU. axyU inactivation in the mutants led to a decrease in MICs of ciprofloxacin (8- to 16-fold), levofloxacin (4- to 8-fold), doripenem (4-fold), doxycycline (4-fold), minocycline (4-fold), and chloramphenicol (≥4-fold). Interestingly, axySUV is present in only about 50% of available A. xylosoxidans genomes, whereas ainCDJ is detected in all A. insuavis genomes. Conclusions: This study demonstrated that AinCDJ overproduction is involved in the acquired resistance of A. insuavis to cefepime, meropenem, doripenem, fluoroquinolones, minocycline, doxycycline, tigecycline, and chloramphenicol and that AxySUV overproduction is involved in the acquired resistance of A. xylosoxidans to meropenem, fluoroquinolones, minocycline, doxycycline, and chloramphenicol. Full article

Background/Objectives: The prevalence of Achromobacter xylosoxidans is increasing in people with Cystic Fibrosis (pwCF), yet its clinical pathogenicity remains controversial. The objective of this study was to chart the longitudinal prevalence and examine clinical associations before and after infection. Methods: This observational, retrospective study was conducted at a single CF center over a 14-year period. Data were collated from patient charts and clinic databases. Patients with Achromobacter sputum cultures were compared to those without the bacterium and analyzed according to whether they had single, intermittent, or chronic infections. Results: During the study period, an annual average of 124 pwCF were followed up at our clinic, with a median age of 13.6 years (IQR = 7.6–27.7). The Achromobacter detection rate increased from 0 to 6.1%. Twenty-three percent (29/124) of patients had at least one positive culture. The median age at acquisition was 17 years (IQR = 14.5–33). At the time of acquisition, the median FEV₁ was 81% (IQR = 46–94), compared to 90% (IQR = 72–99) for patients without Achromobacter, p < 0.001. Patients with Achromobacter tended to demonstrate more chronic Pseudomonas (55% vs. 27%, p = 0.06) and pancreatic insufficiency (66% vs. 47%, p = 0.07). At two years post-acquisition, the median FEV₁ for patients with intermittent and chronically infected decreased by 11.5% (IQR = −3.75–7.5), compared to 1.5% (IQR = −2.5–12.5) for those with a single positive culture, p = 0.03. Similarly, pulmonary exacerbations per year became more frequent post-acquisition in intermittent and chronically infected patients: Median (range) 2.5 (0–8) pre-, versus 3.0 (0–9) post-acquisition, p = 0.036. Conclusions: Chronic and intermittent infection with Achromobacter were associated with accelerated lung function decline and increased exacerbation frequency. Larger prospective studies are needed to confirm these findings and examine the effect of eradication on the clinical course. Full article

The Achromobacter genus comprises 22 species and various genogroups. Some species with higher virulence or antibiotic resistance are more likely to cause chronic infections in people with cystic fibrosis (CF). Current identification methods often fail to accurately distinguish between the species or result in misidentifications due to biochemical similarities. This study aims to develop an accurate qPCR protocol for species-level identification that is applicable in clinical diagnostic laboratories. Whole-genome sequencing of clinical isolates from different Achromobacter species identified species-specific single-nucleotide polymorphisms (SNPs) in two 16S gene regions. Based on these SNPs, two sets of primers and qPCR probes were designed to generate unique identification profiles. Thermal profiles were optimized, and qPCR was performed on serial bacterial DNA dilutions to determine the detection limit (LOD). Four probes successfully identified three species: A. xylosoxidans, A. dolens, and A. insuavis. Two additional probes were designed for novel genotypes unrelated to publicly available sequences. The LOD ranged from 0.005 pg/µL to 1 pg/µL. Combined probes achieved 100% sensitivity, with specificity ranging from 97.95% to 100%. This qPCR protocol enables accurate species identification, overcoming the limitations of current methods, and represents a reliable tool for clinical diagnostics. Full article

Bacteria actively degrade polymeric materials due to high biochemical activity and the ability to form biofilms. In order to expand our knowledge about soil bacterial biodiversity on the surface of artificial materials from the soil of Chernihiv (Ukraine), in this study, the bacterial strain PET1 was isolated from the biofilm formed on the poly(ethylene terephthalate) bottle material taken from soil. The strain was isolated and purified on Postgate’s “C” medium and modified by us (using poly(ethylene terephthalate) as the only source of carbon). The PET1 strain was identified as Achromobacter xylosoxidans based on a complex of microbiological and molecular genetic features. This study is the first report of the isolation of an A. xylosoxidans strain from a biofilm on the surface of poly(ethylene terephthalate) collected from the soil. Considering the growing interest of researchers in the problem of biodegradation of plastics, attention should be paid to the potential of A. xylosoxidans as biodegradation agents. The involvement of bacteria of the genus Achromobacter in the biodegradation of artificial polymers (polyvinyl chloride, high-density polyethylene, nylon) opens up prospects for the isolated strain PET1 to be studied and, possibly, applied as a biodegrader of poly(ethylene terephthalate). Full article

In the present work, the impact of three new bacterial strains and their consortium on composting was evaluated using textile waste as a main substrate mixed with paper, cardboard and green waste, The effectiveness of these micro-organisms in accelerating organic matter degradation was tested. For bioaugmentation of composting, three concentrations (4%, 6% and 8%) were applied. Among the three strains tested, one strain and the consortium demonstrated high organic matter degradation potential, achieving a total organic carbon concentration between 19–21%, total Kjeldahl nitrogen between 1.29–1.56%, a C/N ratio between 13–16%, and a temperature exceeding 55 °C. In the current study, mature compost was attained in 10 weeks, instead of the 44 weeks required for conventional composting and the 12 weeks achieved with other strains previously used. Identification of the strains by 16S rRNA sequencing revealed that they belonged to Bacillus sp., Paenibacillus sp., and Enterobacter aerogenes, respectively. These strains are recognized for their remarkable potential to breakdown a broad variety of organic matter, including lignocellulosic molecules. Furthermore, incorporation of bacteria into the waste mixture (either separately or as a consortium) extended the thermophilic phase by 2 weeks in this study, especially Bacillus sp., Paenibacillus sp. and consortium, leading to a significant reduction in compost production time. It is noteworthy that the efficacy of these strains was considerably greater compared with the three previous strains (i.e., Streptomyces cellulosae, Achromobacter xylosoxidans and Serratia liquefaciens), which were isolated from compost and used for bioaugmentation in a previous study. Our results demonstrate that bioaugmentation by endogenous microbial strains and/or their consortium significantly accelerates the composting process. Full article

This study aimed to explore the phenotype and relationship of drug resistance genes in livestock and poultry farm wastewater and drinking water reservoirs to provide evidence for the transmission mechanisms of drug resistance genes, in order to reveal the spread of drug resistance genes in wastewater from intensive farms in Central China to urban reservoirs that serve as drinking water sources and provide preliminary data for the treatment of wastewater from animal farms to reduce the threat to human beings. DNA extraction and metagenomic sequencing were performed on eight groups of samples collected from four water reservoirs and four related wastewaters from animal farms in Central China. Metagenomic sequencing showed that the top 20 AROs with the highest abundance were vanT_gene, vanY_gene, adeF, qacG, Mtub_rpsL_STR, vanY_gene_, vanW_gene, Mtub_murA_FOF, vanY_gene, vanH_gene, FosG, rsmA, qacJ, RbpA, vanW_gene, aadA6, vanY_gene, sul4, sul1, and InuF. The resistance genes mentioned above belong to the following categories of drug resistance mechanisms: antibiotic target replacement, antibiotic target protection, antibiotic inactivation, and antibiotic efflux. The resistomes that match the top 20 genes are Streptococcus agalactiae and Streptococcus anginosus; Enterococcus faecalis; Enterococcus faecium; Actinomyces viscosus and Bacillus cereus. Enterococcus faecium; Clostridium tetani; Streptococcus agalactiae and Streptococcus anginosus; Streptococcus agalactiae and Streptococcus anginosus; Acinetobacter baumannii, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum, Corynebacterium jeikeium, Corynebacterium urealyticum, Mycobacterium kansasii, Mycobacterium tuberculosis, Schaalia odontolytica, and Trueperella pyogenes; Mycobacterium avium and Mycobacterium tuberculosis; Aeromonas caviae, Enterobacter hormaechei, Vibrio cholerae, Vibrio metoecus, Vibrio parahaemolyticus, and Vibrio vulnificus; Pseudomonas aeruginosa and Pseudomonas fluorescens; Staphylococcus aureus and Staphylococcus equorum; M. avium, Achromobacter xylosoxidans, and Acinetobacter baumannii; Sphingobium yanoikuyae, Acinetobacter indicus, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, and Providencia stuartii. Unreported drug resistance genes and drug-resistant bacteria in Central China were identified in 2023. In the transmission path of drug resistance genes, the transmission path from aquaculture wastewater to human drinking water sources cannot be ignored. For the sake of human health and ecological balance, the treatment of aquaculture wastewater needs to be further strengthened, and the effective blocking of drug resistance gene transmission needs to be considered. Full article

Achromobacter spp. are intrinsically resistant to multiple antibiotics and can also acquire resistance to those commonly used for the treatment of respiratory infections, especially in patients with cystic fibrosis. The aim of this study was to perform the genetic and biochemical characterization of AXC-2 from A. ruhlandii and to analyze all available AXC variants. Steady-state kinetic parameters were determined on a purified AXC-2 enzyme. It exhibited higher catalytic efficiencies towards amino-penicillins and older cephalosporins, while carbapenems behaved as poor substrates. Phylogenetic analysis of all bla_AXC variants available in the NCBI was conducted. AXC was encoded in almost all A. ruhlandii genomes, whereas it was only found in 30% of A. xylosoxidans. AXC-1 was prevalent among A. xylosoxidans. AXC variants were clustered in two main groups, correlating with the Achromobacter species. No association could be established between the presence of bla_AXC variants and a specific lineage of A. xylosoxidans; however, a proportion of AXC-1-producing isolates corresponded to ST 182 and ST 447. In conclusion, this study provides valuable insights into the genetic context and kinetic properties of AXC-2, identified in A. ruhlandii. It also provides a thorough description of all AXC variants and their association with Achromobacter species and various lineages. Full article

High salt levels in soil can severely limit plant development and diminish the positive effect of plant-growth-promoting rhizobacteria (PGPR). However, extracts of organisms adapted to high salinity, such as Opuntia ficus-indica (OFI) and Enteromorpha intestinalis (EI), can restore the growth of PGPR. Therefore, we used OFI or EI extracts and their combination with the PGPR Achromobacter xylosoxidans BOA4 to evaluate salt stress relief in tomato (Solanum lycopersicum). The experimental setup consisted of a plant pot trial under greenhouse conditions with 12 treatments: control, irrigation with OFI extract; EI extract; BOA4-inoculated plus OFI extract and BOA4-inoculated plus EI extract under no salinity or salinity conditions (150 mM NaCl). The percentage of germination, and plant’s fresh and dry weight were registered 30 and 46 days after sowing. At 46 days, the ratio between proline and glutamic acid concentration (PR/GA) was determined, expecting high PR/GA ratios in plants more responsive to salt stress since proline is an osmolyte mainly synthesized from glutamate. The results showed that 52% of the control seeds under salt stress germinated, a figure that was increased to 92% in OFI-treated seeds. Tomato plants were shown to be very sensitive to salt stress since the dry weight was ca. one fourth that of the plants grown without salinity. However, EI or BOA4 plus EI stimulated plant biomass by ca. 3 times compared to the control with salt, restoring plant biomass to values comparable to those of control plants grown without salinity. The joint treatments with BOA4 and EI or OFI caused distinct PR/GA levels in plant tissues. An inverse relationship between the sum of relative shoot proline and glutamic acid contents and shoot biomass accumulation was observed, namely in treatments accumulating more biomass under no salinity and salinity conditions. This indicates that the proline/glutamate pathway represents a carbon sink that is needed to fight stress and is competing with the carbon flow used for growth. Full article

Achromobacter species colonization of Cystic Fibrosis respiratory airways is an increasing concern. Two adult patients with Cystic Fibrosis colonized by Achromobacter xylosoxidans CF418 or Achromobacter ruhlandii CF116 experienced fatal exacerbations. Achromobacter spp. are naturally resistant to several antibiotics. Therefore, phages could be valuable as therapeutics for the control of Achromobacter. In this study, thirteen lytic phages were isolated and characterized at the morphological and genomic levels for potential future use in phage therapy. They are presented here as the Achromobacter Kumeyaay phage collection. Six distinct Achromobacter phage genome clusters were identified based on a comprehensive phylogenetic analysis of the Kumeyaay collection as well as the publicly available Achromobacter phages. The infectivity of all phages in the Kumeyaay collection was tested in 23 Achromobacter clinical isolates; 78% of these isolates were lysed by at least one phage. A cryptic prophage was induced in Achromobacter xylosoxidans CF418 when infected with some of the lytic phages. This prophage genome was characterized and is presented as Achromobacter phage CF418-P1. Prophage induction during lytic phage preparation for therapy interventions require further exploration. Large-scale production of phages and removal of endotoxins using an octanol-based procedure resulted in a phage concentrate of 1 × 10⁹ plaque-forming units per milliliter with an endotoxin concentration of 65 endotoxin units per milliliter, which is below the Food and Drugs Administration recommended maximum threshold for human administration. This study provides a comprehensive framework for the isolation, bioinformatic characterization, and safe production of phages to kill Achromobacter spp. in order to potentially manage Cystic Fibrosis (CF) pulmonary infections. Full article

Power generation and wastewater treatment are two great challenges for sustainable development. Microbial fuel cells (MFCs) are a sustainable alternative that can generate bioelectricity in the bioremediation process of wastewater. For this reason, the objective of this research was to generate bioelectricity through double-chamber microbial-combustion cell systems from wastewater from the Covicorti Wastewater Treatment Plant (PTARC) in the anodic chamber and electrogenic bacteria such as Stenotrophomonas maltophilia, Acinetobacter bereziniae, and Achromobacteria xylosoxidans in the cathode chamber, respectively. Measurements of the voltage, current, power density, current density, and optical density of the bacteria and biochemical oxygen demand (BOD) were made. In addition, a metagenomic analysis of the wastewater sample was performed. It was shown that the MFC with A. xylosoxidans generated the highest voltage peak (1.01 ± 0.06 V) on day 24, while the MFC with S. maltophilia generated the highest current value (0.71 ± 0.02 mA). The pH levels were slightly alkaline, and the maximum anodic conductivity value was presented by the MFC with A. cerevisiae, with a peak value of 81 ± 2 mS/cm on day 24. On the other hand, a maximum power density and current density of 195,493 ± 4717 mW/m² and 4987 A/cm², respectively, were obtained in the MFC with A. xylosoxidans. Finally, the metagenomic analysis identified the predominant phyla of Proteobacteria present in wastewater samples capable of generating electrical energy as Bacillota, Pseudomonadota, Bacteroidota, Actinomyketone, and Campylobacterota. Full article

Cefiderocol is a new siderophore cephalosporin that is effective against multidrug-resistant Gram-negative bacteria, including carbapenem-resistant strains. The aim of this study was to evaluate the activity of this new antimicrobial agent against a collection of pathogens using broth microdilution assays and to analyze the possible mechanism of cefiderocol resistance in two resistant Klebsiella pneumoniae isolates. One hundred and ten isolates were tested, comprising 67 Enterobacterales, two Acinetobacter baumannii, one Achromobacter xylosoxidans, 33 Pseudomonas aeruginosa and seven Stenotrophomonas maltophilia. Cefiderocol showed good in vitro activity, with an MIC < 2 μg/mL, and was able to inhibit 94% of the tested isolates. We observed a resistance rate of 6%. The resistant isolates consisted of six Klebsiella pneumoniae and one Escherichia coli, leading to a resistance rate of 10.4% among the Enterobacterales. Whole-genome sequencing analysis was performed on two cefiderocol-resistant Klebsiella pneumoniae isolates to investigate the possible mutations responsible for the observed resistance. Both strains belonged to ST383 and harbored different resistant and virulence genes. The analysis of genes involved in iron uptake and transport showed the presence of different mutations located in fhuA, fepA, iutA, cirA, sitC, apbC, fepG, fepC, fetB, yicI, yicJ, and yicL. Furthermore, for the first time, to the best of our knowledge, we described two Klebsiella pneumoniae isolates that synthesize a truncated fecA protein due to the transition from G to A, leading to a premature stop codon in the amino acid position 569, and a TonB protein carrying a 4-amino acid insertion (PKPK) after Lysine 103. In conclusion, our data show that cefiderocol is an effective drug against multidrug-resistant Gram-negative bacteria. However, the higher resistance rate observed in Enterobacterales underlines the need for active surveillance to limit the spread of these pathogens and to avoid the risks associated with the emergence of resistance to new drugs. Full article

The aim of this study was first to examine the prevalence of bacteria-associated loss of sperm quality in samples from insemination centers during a seven-year semen monitoring program and, second, to investigate the growth dynamic of four different multidrug-resistant bacterial species and their impact on sperm quality during semen storage. A reduced sperm quality associated with bacterial contamination was found in 0.5% of 3219 of the samples from insemination centers. In samples spiked with Serratia marcescens and Klebsiella oxytoca, bacterial growth by six log levels was seen during storage at 17 °C, causing loss of sperm motility, membrane integrity, membrane fluidity, and mitochondrial membrane potential at >10⁷ CFU/mL (p < 0.05). Storage at 5 °C in the Androstar Premium extender efficiently inhibited their growth. Achromobacter xylosoxidans and Burkholderia cepacia showed limited growth up to two log levels at 17 °C and did not impair sperm quality. In conclusion, spermatozoa tolerate moderate loads of multidrug-resistant bacteria, and hypothermic, antibiotic-free semen storage effectively limits bacterial growth. The constant use of antibiotics in semen extenders should be reconsidered. Full article

Chronic lung infections in cystic fibrosis (CF) patients are triggered by multidrug-resistant bacteria such as Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Stenotrophomonas maltophilia. The CF airways are considered ideal sites for the colonization and growth of bacteria and fungi that favor the formation of mixed biofilms that are difficult to treat. The inefficacy of traditional antibiotics reinforces the need to find novel molecules able to fight these chronic infections. Antimicrobial peptides (AMPs) represent a promising alternative for their antimicrobial, anti-inflammatory, and immunomodulatory activities. We developed a more serum-stable version of the peptide WMR (WMR-4) and investigated its ability to inhibit and eradicate C. albicans, S. maltophilia, and A. xylosoxidans biofilms in both in vitro and in vivo studies. Our results suggest that the peptide is able better to inhibit than to eradicate both mono and dual-species biofilms, which is further confirmed by the downregulation of some genes involved in biofilm formation or in quorum-sensing signaling. Biophysical data help to elucidate its mode of action, showing a strong interaction of WMR-4 with lipopolysaccharide (LPS) and its insertion in liposomes mimicking Gram-negative and Candida membranes. Our results support the promising therapeutic application of AMPs in the treatment of mono- and dual-species biofilms during chronic infections in CF patients. Full article

Employing floating treatment wetlands (FTWs) and constructed wetlands (CWs) is one of the most eco-friendly strategies for the bioremediation of water contaminants. Here, the efficiency of FTWs and CWs was compared for the degradation of phenanthrene-contaminated water for the first time. The FTWs and CWs were established by vegetated Phragmites australis in phenanthrene (1000 mg L⁻¹)-contaminated water. Both wetlands were augmented with a bacterial consortium of four bacterial strains: Burkholderia phytofirmans PsJN, Pseudomonas anguiliseptica ITRI53, Arthrobacter oxydans ITRH49, and Achromobacter xylosoxidans ITSI70. Overall, the wetlands removed 91–93% of the phenanthrene whilst the augmentation of the bacterial strains had a synergistic effect. In comparison, the CWs showed a better treatment efficiency, with a 93% reduction in phenanthrene, a 91.7% reduction in the chemical oxygen demand, an 89% reduction in the biochemical oxygen demand, and a 100% reduction in toxicity. The inoculated bacteria were found growing in the shoots, roots, and water of both wetlands, but were comparatively better adapted to the CWs when compared with the FTWs. Similarly, the plants vegetated in the CWs exhibited better growth than that observed in the FTWs. This study revealed that the FTWs and CWs vegetated with P. australis both had promising potential for the cost-effective bioremediation of phenanthrene-contaminated water. Full article